SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '253103b099d699c45405075e2d70a71145d94b54d061da9f7422410269d91190' 
  AND token = '7DuxtwGRRsNcfUZuw/x4jBCcE5mT6zFh0eBqzfGrq/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}